Speaker
Description
Despite the rich physics potential of the intermediate diphoton mass range of 130-200\,GeV, this regime remains one of the least constrained at the ATLAS experiment, motivating dedicated searches in the $\gamma\gamma + 0\ell1\tau$ final state. This work presents a study using Run~3 ATLAS data recorded between 2022 and 2024 at $\sqrt{s} = 13.6$\,TeV, corresponding to an integrated luminosity of 164\,fb$^{-1}$. Background contributions from $V\gamma\gamma$, Single Higgs production, $t\bar{t}\gamma\gamma$, and $\gamma\gamma +$ jets are modelled by fitting candidate functional forms to the $m_{\gamma\gamma}$ sideband regions and extrapolating into the signal window of 146-154\,GeV. A cut flow
table documents the weighted event yield at each selection stage, identifying areas of significant event loss and motivating selection optimisation. RNN-based working points, namely Loose, Loose with electron rejection, Medium, and Tight, are applied to the hadronic tau identification. A spurious signal test is performed to validate the background fitting function, followed by parameterisation of the signal shape using a Double-Sided Crystal Ball (DSCB) function, completing the signal and background modelling framework for this intermediate-mass regime.
| Apply for student award at which level: | MSc |
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| Consent on use of personal information: Abstract Submission | Yes, I ACCEPT |